#include <iostream>

/* run this program using the console pauser or add your own getch, system("pause") or input loop */

using namespace std; 

	int f(int n){

	int a=1;

	for(int i=1;i<=n;i++)
	a*=i;
	return a;
}
	int main() {
	cout<<"f(3)="<<f(3)<<endl;
	cout<<"f(5)="<<f(5)<<endl;
	cout<<"f(7)="<<f(7)<<endl;

	return 0;
}
